The present invention relates to a sheet conveying apparatus connected between an image forming apparatus such as a printer and a post-processing apparatus and to an image forming system.
There has been used a finisher as a post-processing apparatus that conducts post processing such as a punching process and a stapling process, and various types of speed adjusting device have been employed because a sheet conveyance speed of an image forming apparatus is usually higher than that for post processing. With respect to a speed adjustment manner, there are known, for example, a manner wherein a conveyance speed is synchronized between a printer and a finisher (Unexamined Japanese Patent Application Publication No. 2002-311659), a manner to cope with changes of the printer side conveyance speed at the finisher side (Unexamined Japanese Patent Application Publication No. 10-111585) and a manner to make a carry-in roller on the finisher side to be high in speed to conduct receipt at high speed and to adjust a conveyance speed inside the finisher (Unexamined Japanese Patent Application Publication No. 2000-62998) and there are further known a manner where a sheet interval is adjusted by the printer depending on a type of post processing for the post processing conducted for plural sheets (Unexamined Japanese Patent Application Publication No. 11-208979) and a manner to adjust the speed by utilizing stacking on an intermediate tray of the finisher (Unexamined Japanese Patent Application Publication No. 2001-72308).
Since a post-processing apparatus is generally designed and developed as an apparatus exclusive for an image forming apparatus to which the post-processing apparatus is connected, a huge amount of cost is required for development of the apparatus even when the post-processing apparatus is one conducting the same processing.
Therefore, in Unexamined Japanese Patent Application Publication No. 2004-26358, there is proposed a relay conveying apparatus that adjusts operating speeds for the image forming apparatus and the post-processing apparatus, so that a conventional post-processing apparatus may be connected to the image forming apparatus even when specifications of the image forming apparatus are changed.
However, the structure of the aforesaid relay conveying apparatus causes the apparatus to be large in size, which is a problem.